Replace Tensioner Pulley Bearing on 2.7 Hilux

9 Sept 2009

Problem: Tensioner pulley became noise. I got a quote from Toyota Agents and they quoted me R1,400 for a new one. They said I had to buy the whole unit and cannot get the pulley only.

Solution: Removed the bearing and replaced the bearing only which cost me R38.67

This is how to do it:

NOTE: You must use a good quality bearing like SKF, NSK or Timken and it must be a sealed bearing.

Because the pulley does not have a circlip which hold the pulley the agents do not want to replace the bearing only, they say you have to replace the whole unit. In the picture above you can see that the indentations marks hold the bearing in place.

First you have to remove the pulley. Note that there are two bolts. The one which is in a vertical position is the tensioner bolt and you have to loosen this one LAST. Do not try to loosen this before you have loosened the main bolt fist.

At the front of the pulley is a horizontal bold (A in photo below) which holds the pulley. Loosen this bolt (A) first, just a little bit. Then adjust the other bolt (B) in order to remove tension from the pulley. Once the fan belt is not tight anymore you can remove the front (horizontal) bolt completely and remove the pulley. Both these bolts take a 14mm spanner. You must turn both bolts anti clockwise to loosen.

Once remove have a look at the the spacer at the back before you remove it. If you put it back in the wrong way around the pulley will not turn.

Now take a small chisel, old screw driver or punch to lightly hit the indentations back so that you can remove the washer which is on top of the bearing. I used an old screw driver and old injector tip. These old injector tips are very hard and sharp and is the ideal "punch" to use for delicate jobs like this.

Once you removed the indentations you can turn the pulley around and hit the bearing from the back to remove it. Do not bother taking the washer out first because it will come out when you remove the bearing. It is of course better to rather use a press if you have one.

Once you removed the old bearing you can now put in the new bearing. The bearing size is NSK 6301. It has a OD of 37mm, ID 12mm and is 12mm thick with rubber seals.

Putting the bearing back in needs some skill. You must nether hit the bearing's inside with a hammer. You can only lightly tap the outside ring if you know how to. You must do this carefully. You can also put the old bearing on top of the new one and rather hit the old bearing. See the next two pics.

Hitting it directly on outer edge

Old bearing on top

Once the bearing started to go in you can put it in the vice to press it in if you have a vice or the best way of course is to use a press and press it back in. Note that while pressing it you also put pressure on the old bearing and not the new one in order to prevent damage to the new bearing.

Press with vice

Press

Once completed you have to put back the washer and then take a centre punch and make new indentations marks. These indentations do not carry a lot of load. All it have to do is prevent the bearing from moving outwards.

Replace the front washer and rear spacer.

Now put the pulley back in. Tighten bolt A by hand only. Then put the fan belt in place and set the tension of the fan belt with bolt B. Turn it clockwise for more tension and anti-clockwise to loosen. Once the tension is correct then only tighten Bolt A.

I am not sure what the correct tension for the fan belt is but the general rule I use is to twist the fan belt When it reach the point where I cannot twist it more than 90 degrees then it is OK.

TIP: While you are busy with this you might as well check your fan belt If it has cracks in rather replace it. You will note that it is behind the fan. To remove the fan belt just move it over the fan blades one at a time.

Idea: There was a suggestion that one cut a groove in the pulley for a circlip. This will make the tensioner pulley serviceable. Thus you can easily replace the bearing next time. Because the casing of the pulley is only about 2mm thick I did not feel at ease to cut a 1mm deep grove in the pulley. So I decided to rather investigate the matter further before doing it.

If nothing goes wrong this whole operation should not take you longer than 40 minutes.

Bearing No NSK 6301